when making a starter, do you just let it sit or agitate/swirl it every so often? I know some people do their starters on stir plates, so I would think keeping yeast more in suspension would be better.

I would have to disagree with you Proflight, when it comes to a starter you are trying to up the cell count as much as possible and this happens during the aerobic stage of the yeast life cycle. so you would wan to keep that going for as long as possible. I usually swirl my starters every time I walk by it on the counter. A stir plate would be ideal. I also use my O2 stone on it. I am not saying that you have to in order to get a good viable starter I just think that you would get a higher cell count keeping more O2 in the solution.